This invention relates generally to a guiding or positioning apparatus for use during hitching a pickup truck or other towing vehicle to a trailer or other towed vehicle. More particularly, this invention relates to a positioning apparatus for aligning the coupling elements of the two vehicles as the towing vehicle is backed up or driven toward the towed vehicle and for indicating when the coupling elements are positioned to be coupled.
Hitching a vehicle to a trailer can be a long and frustrating process, especially when attempted by a single person. Because the coupling elements (i.e., ball and hitch) on the vehicle and trailer are normally not visible from the driver's seat, the driver must periodically stop the vehicle and inspect the alignment and position of the ball and hitch before moving the vehicle closer to the trailer. Even with frequent visual inspections, some misalignment of the ball and hitch normally result. A driver must then repeat the process or, if possible, manually shift the tongue and thus the hitch of the trailer over the ball so that the two vehicles can be coupled. Complicating the maneuvering is the fact that a driver can become easily confused as to which direction to turn the front wheels in order to back the vehicle in the desired direction. Many previously proposed devices require the driver to be able to see a flag or light attached to the trailer, permanently mount and wire a device to the vehicle, or have poor lateral precision and no warning when the vehicle is about to contact the hitch of the trailer, which frequently leads to damage of the towing vehicle.
Many proposed devices use switches or magnets to indicate alignment. For instance, U.S. Pat. No. 5,108,123 to Rubenzik, indicates a magnet placed on the surface below the hitch. Those familiar with the art will realize that the operating range of magnetic switches is limited. This approach limits the vehicle to being in a precise position before an indication is available.
Other proposed devices utilize ultra-sonic means, such as U.S. Pat. No. 5,191,328 to Nelson, to provide distance information. Due to the short transit time of the sonic wave at distances of less than twelve inches, and lack of a well-defined target, the accuracy of these devices is poor.
Devices that require permanent mounting to either vehicle, such as U.S. Pat. No. 6,100,795 to Otterbacher, are subject to damage while the vehicle is used for other purposes.
Additionally some devices, when permanently mounted, may obscure the license plate of the vehicle or provide a safety hazard to persons walking behind the vehicle such as U.S. Pat. No. 4,938,495 to Beasley.
Devices that require internal wiring are difficult to install and the wiring is subject to damage during normal vehicle use. Dangling cords, such as cigarette lighter plugs, can be a distraction for the driver as well as a safety hazard.
Some other proposed devices use a display limited to a single indicator of lateral position error. This does not inform the driver of the amount of error or needed correction. This is little better than visual mechanical means.